What's the purpose of a 30 amp fuse in a dryer that's on a 30 amp breaker?

I am guessing it is for the people who put them on 50 amp fuses or breakers. This happens more on fuses when the homeowner has a blown fuse and replaces it with whatever they have. Or it could be for if the breaker fails to trip. It seems unnecessary but hey just one more thing for us to go out and make money on lol.

I've seen these on the more expensive GE Profile dryers. Its on the inside back panel near the bottom. From what I've seen, it goes from L2 (or L1 on gas) on the terminal block to a thermal fuse. You can get these fuses at any hardware store.